Most crop management decisions are interrelated, the success of one often depending on another. The two management areas discussed in this final segment are more related than the others. For instance, the well-fertilized field will produce very little if there is no water and vice versa. The lesson discusses soil sampling and testing to determine fertilization needs, methods of application and the various types of fertilizer available; the techniques farmers use to estimate their irrigation needs -- from relying on experience and drilling into the soil to determine moisture content to the more sophisticated techniques of using tensiometers or gypsum blocks -- are detailed.